Stop Trafficking of Pills Act or STOP Act - Amends title XIX (Medicaid) of the Social Security Act (SSA) to require state Medicaid plans to: (1) identify prescription drugs that present a high-risk of misuse or overutilization, (2) establish a dosage level for each such drug that would be deemed excessive in the absence of evidence of medical necessity, (3) identify Medicaid-eligible individuals who are either receiving a prescription drug at excessive dosage levels or who have been convicted of a drug-related offense, and (4) ensure that they are assigned to a state-established restricted recipient program.
Requires a state to establish a Medicaid Lock-in Program to ensure that a high-risk prescription drug user is assigned to: (1) a single and exclusive physician for purposes of receiving any medical assistance related to a prescription drug, and (2) a single and exclusive pharmacy to receive any physician-prescribed drug.
Requires a state to establish a Medicaid prescription drug restriction program to ensure that the state claims processing system does not permit a prescription drug to be dispensed to a high-risk prescription drug user more than once every 20 days.
Amends part D (Miscellaneous) of SSA title XXVIII (Medicare) to direct the Secretary of Health and Human Services (HHS) to establish a similar restricted recipient program for high-risk prescription drug users under the Medicare program.